Firing mechanism for recoilless shoulder mounted guns



Aug. 30, 1949. c JQHNSTQN 2, ,328

FIRING MECHANISM FOR RECOILLESS SHOULDER MOUNTED GUNS 4 Sheets-Sheet 1 Filed July 13. 1944 WINVENTOR. I V ,MIZA Bim ig. I 94 l l I l I I 11.

Aug. 30, 1949. JQHNSTQN 2,480,328

' v FIRING MECHANISM FOR RECOILLESS SHOULDER MOUNTED GUNS Filed July 13. 1944 4 Sheets-Sheet 2 m T 2.7 1 [EM];

BY MY%,

Aug- 30, H. c. JOHNSTON FIRING MECHANISM FQR RECQILLES$ SHOULDER MOUNTED GUNS Filed July' 15, 1944 4 Sheets-Sheet 3 341C. ,INVENTOR.

' BY W M? I so i Aug. 30, 1949. H. c. JOHNSTON FIRING MECHANISM FOR RECOILLESS SHOULDER MOUNTED GUNS 4 Sheets-Sheet 4 Filed July 13. 1944 INVENTOR.

Patented Aug. 30, 1949 FIRING MECHANISM FOR RECOILLESS SHOULDER MOUNTED GUNS Hal 0. Johnston, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application July 13, 1944, Serial No. 544,676

6 Claims. (01. 42-69) This invention relates to ordnance and more particularly to an improved type of recoilless shoulder mounted gun. 1

It is an object of this invention to provide a gun which may be carried on the shoulder of one person and which may be cooked and reloaded by another person without throwing the carrier off balance.

Another object of this invention is to provide an improved safety means for preventing accidental or premature firing of the gun. More particularly it is an object of this invention to provide a safety means for preventing the firing of the gun before the person loading the gun has had time to move to a safe position.

A further object of this invention is to provide a gun which is suitable for mass production.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is an elevational view showing a gun embodying my invention;

Fig. 2 is a fragmentary sectional view showing the arrangement of the sear and the sear operating mechanism;

Fig. 3 is an end view of the rotatable breech block;

Fig. 4 is a sectional view taken on line 44 of Fig. 3;

Fig. 5 is an elevational view of the one hinge bracket which supports the breech block and the hammer mechanism;

Fig. 6 is a fragmentary sectional View showing a portion of the safety mechanism;

Fig.7 is a view with parts broken away, showing a portion of the trigger mechanism; and

Fig. 8 is an end elevational view of the gun.

Referring now to the drawings, reference numerals l0, l2 and i4 designate generally the chamber of the gun, the gun barrel and the breech block, respectively. The breech block M is rotatable relative to the hinge bracket l6 which supports the breech block.

The gun is of the type which is designed to be mounted on the shoulder of a soldier or on a light tripod and is designed to exhaust a portion of the gas through the ports 20 of the breech block l4 so as to counteract any tendency of the gun to recoil. Special cartridges (not shown) are used which allow a portion of the gas to exhaust through the ports 29. As shown in Figs. 3 and 4, the shape of the ports is such that the gasses exhausting therethrough overcome the torsional force produced by the projectile contacting the rifiing 22 formed in the barrel i2.

As shown in Fig. 4, an insert 24 has been provided in the breech block M which serves to guide the firing pin 26. A cap screw 21 holds the insert in place. The hinge bracket I6 is provided with a hammer housing 28 within which the hammer 30 is slidably mounted. A coil spring 32 disposed within the housing 23 biases the hammer towards the firing pin 26. A sear 34 latches the hammer 3B in its rear position when the gun is cooked. The hammer 30 is provided with cam projections, such as the projections 36, which cooperate with the cam surfaces 33 provided on the insert element 24. The arrangement is such that upon rotation of the breech block M by means of the handle t8 the cam surfaces 33 engage the cam segments 36 so as to cam the hammer 3G to the rear against the spring 32 so as to store up energy in the spring 32. The scar 34 is biased into latching engagement with the hammer 3!) by means of the spring ill arranged as shown in Fig. 2. The hammer 30 is provided with a pair of guide pins 39 which slide in slots M in the hammer housing.

The breech block i d is held in place relative to V the hinge bracket I6 by means of the plate 42 (see Fig. 2) which in turn is held in place by means of a plurality of cap screws, such as the cap screw 44, which engage the tapped recesses 45 in the breech block id. Lugs 46 are provided on the breech block M which engage beneath the locking flanges 48 provided adjacent the end of the chamber It]. In order to reload the gun, the

breech block M is rotated the necessary amount to disengage the lugs 46 from the flanges 48 after which it is possible to swing the breech block i4 away from the rear end of the chamber it. The breech block [4 swings about the pivot 5%} which is the main pivot for the hinge bracket it. The pivot pin 59 is carried by the stationary hinge bracket 52 which is secured to the bottom side or" the chamber 10 as shown. The amount of rotation necessary for disengaging the lugs 46 from the locking flanges 48 is enough to cook the gun with the result that no further operation is necessary for cocking the gun. The cooking takes place as the breech block is rotated from the locked position into the unlocked position. As shown in Figs. 3 and 4, a portion of the breech block M is cut away to receive the hinge bracket to. The side walls 53 and 5% formed by the cut away portion serve to limit the rotation of the breech block. Inasmuch as these guns are intended to be supported on the shoulder during operation, it is very essential that the gun be reloaded without the exertion of any force which might tend to throw the carrier off balance. Experience has shown that any pushing or pulling on the gun tends to throw the carrier off balance whereas the rotational forces produced when reloadingthe above-described gun donot have that effect.

Adjacent the front end of the barrel I have provided a combined trigger and safety means disposed within a handle GI]. As best shown in Fig. '7, the trigger comprises a member-62 pivoted within the handle at 54. A safety element 6t mountd -"to'rotate about the shaft I22 carried by the hinge bracket I6. The rear end of the lever =I'2Il i provided with a forked portion I24 ar- -ranged-to operate-the sear pin 34. The lower end 'ofthesear gpin 34 is provided with a head I26 pivoted within the handle *at' this provided with a projecting portion I which is designedto'engage within a notch I2 provided in the trigger element 62. A spring '14 normally "biases the safety element 66 into trigger engaging position. The upper end It of the trigger eIementGZ'is'arranged to project through a slot '33 in the trig- ;gerrod-guide Sllsoas'te engage the trigger rod Sm'echanism'BZ. A springii l pushes against the front end of the trigger rod mechanism as shown. Byvirtue'of the above described arrange- 'ment it is apparent'that in order to operate the ftriggers .62 Lit" is necessary to first push in on the :safet elenrent 66 and then push in on t.e trigger 62 'The'ha'ndleisiliissecured to the barrel is by z'i'n'eans ofia suitable mounting strap arrangement .86. Theitriggeri'ro'dmechanism eompr'ses a first .or front trigger rod section as which extends .from'ztheihandleififl'-'towards'the rear end of the barrel Ii2 and fa second trigger rod section Gil whichisoifset from the first section and extends v -a-lon'gthe'i-lower side of the firing chamber it. 'The rodsecti'on-lsli is s'lidably mounted within the :protectivettube SZas shown. The second or rear trigger ro'd sectionifiii is slidably mounted within aisimilar protective tube 94 which is secured to -the lower side of the firing chamber It. As shown in -Figf6, the first section is provided with a'depending'arm ilfi'which'is adapted to engage "withina'hole I00 provided in the flat spring I 62. The spring I02 'is 'carried by the second trigger zrod-section il. The spring I $2 is a flat spring itvhih wouldnormally assume a position out of engagementwith'theelelnent 96 (as shown in :dotted 1ines 1but which ma be camrnedinto engagement withthe element 96 by means of the irotatable cam element Ilit carried on the shaft 1% -whichiin'turn is supported by the housing iIrIl'I. :A setscreW Hi8 prevents relative rotation between the camIIJO and the shaft H56. A knob fl'IEIJ is provided on'the outer end of the shaft Iiiii "ffOl manually manipulating the cam I84. Referring to Fig. 6, it is obvious-that when the front trigger rod section '88 is pulled forward by the :trigger 62, the projecting arm'fiii pulls the rear 'trigger'rod'efl forward and also causes the cam ilil l'to'be rotated out of spring lifting position. By virtue of this construction, a second pull on 'thetrigger-SZ will not cause operation of the rear trigger rod section 99 unless and until the cam I0 5 hasbeen reset was to cam the spring IIl'Z into its upper position in engagement with the element 96. It is also apparent that it would be impossible to operate the cam in unless the aperture 109 in the sprin I8 2 is properly lined 'upwith the'projection 96. Thus, if the individual carrying the gun fails to release his pressure on thetrigger 62, it would be impossible to reset the cam -'II'I' I. The mechanism shown in Fig. 6 serves 'very eifec'tivelyas an added safety for preventing prematureoperation of the trigger-rodfiO.

against which the forked portion I24 pushes when iths desiredito-ifire"=the gun. The sear pin has fiatmortiontdirctly above the head I26 which is"straddledbfthe forked portion I24 of the il'ever120.

A .stop I28 carried by the hinge bracket 52 "li'niits'the swinging movement of the hinge bracket I6 which is provided with a stop engagfiing surfaced 3 0 as showrf in Fig. 2.

another, "it is important -to p'rovide the necessary safety "Inea'ns ror 'preventmg the premature firthe exhaust ports in the breech. By virtue of-the :saf'e'ty means i'described' hereinabove theperson loading the gun must-turn ithe' knob M (I so as to reset'ithe s'afety mechanism before the person firing ithe' gunfcanuefiectivelyipull the "trigger and "themesettirigicanionly b'e' dOHe when 'the trigger 'is :in :its :forward: position whereby the safety element 66 will also fhave' a ch'an'c'e to moveinto saietyjposition EE'hu's both of thesafety devices are reset-.betorezeach firingiofithe gun. While-the :form for: embodiment of the invention as hereintdis'closed' con'stitutes a pref erred form it is :to beimderstood that other forms might be adopted as rmaytoom'e within the-s'cope' of": the claims which follow.

What is claimed is as follows: '1. in zafirearmt arfiringmin; affiring pi'n operating mechanism comprising itri-gg'er rod means thavi-ngaazfirst sectiomandra second section, a projection providedzon one of said sections, 'a-substantially fiat spring carried by the 'o'ther:of said sections zand movableifromza first position in interlocked engagement with said projectionto 'a *sec'ond aposition'iout of'interl'o'cked engagement with said projection, said spring being biased out of interlocked position, andm'eans for' manually moving said :springzintothe i'nterlo'cke'd position,

andtrigger means for operating said seotions in unison when "said-spring 21s in 'said :first (position.

:2. -In a'shoulde'ritypeeof firearm,'-me'ans forming -a firing chamberaofia given diametena barrel of smaller" diameter'projecting "from "the front end ofsaidKehamber wlrereby there is "formed an offset in the" outer *c'ontour 'of "the firearm intermediate'theerrdstthereof,*triggermeansadjaizerit the 'front 'en'd of said firearm'gshell firing mechanism including-Ia searadjacerit the re'arend of the firearm, and a pair of trigger-rods -extending rods 'having a projecting -"portion, said second namedrodhavingmeans for releasably engaging "said projecting portion.

3. In a firearm, a firing pin, a firing pin operatin mechanism comprising in combination, a pair of trigger rod sections, means for releasably connecting said sections together whereby a pull on one of said sections may be transmitted to the other of said sections, and connecting means including safety means for automatically disengaging said sections during each operation of said firing pin, trigger means for operating said sections, and manual means for reconnecting said connecting means.

4. In a firearm, a firing pin, a firin pin operating mechanism comprising a pair of trigger rods, means for releasably connecting said rods together so as to operate as one rod, said means comprising an apertured blade spring carried by one of said rods and an arm carried by the other of said rods for engaging in an aperture of said blade spring, said blade spring being biased away from engagement with said arm and arranged to become disengaged from said arm during each operation of said firing pin, and manual means for-moving said spring into enga ement with said arm.

5. In a firearm, a firing pin, a firing pin operating mechanism comprising trigger rod means having a first section and a second section, a projection on one of said sections, a substantially flat spring carried by the other of said sections and movable from a first position in engagement with said projection to a second position out of engagement with said projection, means for disengaging said projection from' said spring upon operation of said rod incidental to firing of the gun, and manually operable means for reengaging said spring with said projection.

6. In a recoilless shoulder type gun adapted to be mounted upon the shoulder of and fired by a first person and to be cocked and loaded by a second person, a barrel, a firing chamber and firing mechanism at one end of the. barrel, a handle located adjacent an intermediate portion of the barrel containing a combined trigger and safety means operable by the first person, said combined trigger and safety means including a continually biased means for normally preventing its efiective operation capable of beingovercome" by the active proper manipulation by the first person, a normally disconnected connectleans extending from said handle and trigger to said firing mechanism and having a normally REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 681,109 Dawson et al. Apr. 20, 1901 795,440 Hammar July 25, 1905 927,070 Pieper July 6, 1909 1,141,285 Swartz June 1, 1915 1,302,524 Dawson et al. May 6, 1919 1,350,961 Farquhar et al Aug. 24, 1920 1,430,662 Lewis Oct. 3, 1922 1,743,472 Meyer Jan. 14, 1930 1,753,072 Stange Apr. 1, 1930 1,867,569 Hor-ger July 19, 1932 2,119,536 Green June 7, 1938 FOREIGN PATENTS Number Country Date 241,574 Great Britain Apr. 29, 1926 308,449 Germany Nov. 2, 1920 

